Indeed, to keep this campaign on the highest possible level worthy of its significance, I have been tempted to make a proposal to our Republican friends: that if they would stop telling lies about us, we would stop telling the truth about them.

Adlai Stevenson (1900–1965) American diplomat, statesman

Speech (1952-09-19), “The New England Tradition,” City Hall, Springfield, Massachusetts
    (Source)

A favorite quip of Stevenson's.